Mononitroalkylanilines, mononitroalkylacylanilines and derivatives thereof and theirmanufacture



Patented May 24, 1938 UNITED STATES PATENT OFFICE MONONITROALKYLANIIJNES, MONONITRO- ALKYLACYLANILINES AND DERIVATIVES THEREOF AND THEIR MANUFACTURE No Drawing. Application January 14, 1931, Se-

rial No. 120,631. 1936 8 Claims.

alkoxy substituents. It relates also to the manufacture of the above-mentioned new derivatives.

These new derivatives are valuable dyestufl intermediates.

We use as starting materials in the process of our invention alkylanilines and their .N-acyl derivatives. in which the alkyl group has 6-18 carbon atoms and is directly attached to the benzene nucleus, and in which there may be other' substituents directly attached to the benzene nucleus, e. g. bromo, chloro, methyl, or alkoxy substituents.

According to the process of our invention we mononitrate the above starting materials. Also according to the process of our invention, we deacylate the products obtained by the mononitration of such of our starting materials as are N-acyl derivatives. The nitration is effected by treating the starting materials with nitrating agents, examples of suitable nitrating agents are nitric acid, mixtures of nitric and sulphuric acids, and copper nitrate in acetic anhydride. The treatment with the nitrating agent may be effected in a suitable medium. When nitrating N-acyl starting materials nitrating medium may be that in which the N-acyl starting materials aliphatic alcohols having 6-18 carbon atoms.

have been made by acylating the corresponding anilines.

The hydrolysis of the mononitrated N-acyl starting materials may be effected by treating them with acid or alkaline hydrolyzing agents, for example, by heating them with hydrochloric acid or aqueous sodium hydroxide solution.

The alkylanilines, which are used as starting materials in the process of our invention, may be made from the corresponding anilines or N-alkylanilines by heating them, in the presence of a halide of zinc or cobalt, with saturated primary In this process the anilines may be wholly or partly replaced by their hydrochlorides or hydrobromides, and the N-alkylanilines may be wholly or partly replaced by their hydrochlorides or hydrobromides, or partly replaced by the hydrochlorides or hydrobromides of the parent anilines. Examples of the alcohols used in making these alkylanilines are hexyl, octyl, decyl, otherwise known as decanol, dodecyl, tetradecyl, hexadecyl,

In Great Britain January 15,

and octadecyl alcohol. Hexadecyl alcohol is the main or sole component of the alcohols obtained by the saponification of spermaceti: it this is obtained by the saponiflcation of spermaceti its purity may depend upon the purity of the spermaceti. Dodecyl and tetradecyl, otherwise known as myristyl alcohol, are obtained by the reduction of the mixed fatty acids obtained from coconut oil and palm oil. Other alcohols are likewise obtainable by reduction of the fatty acids of natural fats and oil (see, for. instance, Bouveault and Blane, Bull. Soc. Chem, Series 3, vol. 31, pages 674 et seq. and 1210 et seq). The alcohols include mixed alcohols, for instance, technical lorol which consists of the mixed alcohols from coconut oil fatty acids. The alkylanilines include those specifically described in the abovementioned specification, although these may not always be pure compounds or single chemical compounds.

The N-acyl derivatives of the alkylanllines may be made from the alkylanilines as acetanilide is made from aniline, for example, by treating the alkylanilines with the halides or anhydrides of, for example, acetic, propionic or benzoic acid. The alkylacetanilides may be made by treating the alkylanilines with acetic anhydride in glacial acetic acid.

The invention may be more particularly described by referring to the mononitratlon of .p-dodecylaniline and of p-dodecylacetanilide. p-Dodecylaniline may be mononitrated in concentrated sulfuric acid to give 3-nitro-4-dodecylaniline. It may be acetylated with acetic anhydride in acetic acid and the resulting p-dodecylacetanilide mononitrated without isolation, to give 2-nitro-4-dodecyiacetanilide, which may be then deacetylated to 2-nitro-4-dodecylaniline.

One object of our invention is the provision of new mononitroalkylanilines, monoalkylacylanilines and derivatives thereof, in which the alkyl group has 6-18 carbon atoms and is directly attached to the benzene nucleus, and in which there may be other substituents directly attached to the benzene nucleus, e. g. bromo, chloro, methyl, or alkoxy substituents.

Another object of our invention is the provision of a process for the manufacture of the new products referred to in the preceding paragraph, which comprises mononitrating alkylanilines and their N-acyl derivatives, in which the alkyl group has 6-18 carbon atoms and is directly attached to the benzene nucleus, and in which there may be other substituents directly attached to the benzene nucleus, e. g. bromo, chloro,

methyl, or alkoxy substltuents, and also the provision of a process which comprises the deacylation of the nitrated N-acyl derivatives.

Further objects of our invention appear hereinafter.

The following examples in which partsare by weight illustrate, but do not limit, the invention:

Example 1.l30 parts of p-dodecyianiline are stirred with 300 parts of acetic anhydride and after a few minutes the mixture is. diluted with 100 parts of glacial acetic acid. To the resulting solution of p-dodecylacetanilide, 35 parts of 95% nitric acid are added in an hour at 30-34" C., the mixture is warmed to 40 C. for half an hour and poured into water. 2-nitro-4-dodecylacetanilide separates as a yellowish-brown solid in over 90% yield, calculated on the p-dodecylaniline. It crystalllaes from alcohol in small yellow crystals, M. P. 74.5-75 C.

Example 2.26.1 parts of p-dodecylaniline are acetylated by adding to 128 parts of acetic anhydride, 14.5 parts of copper nitrate trihydrate, Cu(NOa)z.3Hz0 are added a in half an hour at 10-12" C. with good stirring, stirring is continued for 1 hour at 10-l5 C. andthe temperature'then allowed to rise to about 30 C., heat is then applied and the temperature raised to 50 C. in half an hour. The mixture is cooled and poured into water. 2-nitro-4-dodecylacetanilide separates as a yellowish-brown solid in over 90% yield, calculated on the p-dodecylaniline.

Example 3.110 parts of 2-nitro-4-dodecylacetanilide from Example 1, 260 parts of 36% hydrochloric acid and 300 parts of glacial acetic acid are boiled together for about 2 hours until a test sample gives a clear solution when diluted with water and treated with sodium nitrite. The mixture is then poured into 1,000 parts of water, when 2-nitro-4-dodecylaniline separates as an orange precipitate, M. P. 73-74 0., this is filtered, washed acid-free and dried. The yield is -90%, calculated on the p-dodecylacetanilide. The compound crystallizes from alcohol as an orange crystalline powder, M. P, 74 C.

That the nitro group goes into a position ortho to the acetylamino group is shown by treating the nitroamino compound with bromine when only a monobromo derivative is formed. (See Abderhalden, Handbuch der Biologlschen Arbeitsmethoden, 1933, vol. 2, page 2517.)

Example 4.52 parts of p-dodecylaniline are dissolved in 1870 parts of 99% sulfuric acid and the solution cooled to 0-2 C. A mixture of 14 parts of 92% nitric acid and 40 parts of 99% sulfurlc acid is gradually added below 5 C., the temperature is kept at 5 C. for 2 hours, the mixture is poured on to ice and the precipitate filtered and washed with water. The product, which is the sulphate of 3-nitro-4-dodecylaniline, is converted to the base by stirring with weak aqueous ammonia, the base is filtered, washed with water and dried. It is an orange powder, M. P. 63-65 C., soluble in benzene with an orange colour. It crystallizes from glacial acetic acid in deep orange coloured crystals, M. P. 68 C.

That the nitro group goes into a position meta to the amino group is shown by treating the nitro compound with bromine in aqueous acetic acid when a dibromo derivative is formed.

Example 5.--5 parts of p-decylaniline are added to 40 parts of acetic anhydride and 15 parts of acetic acid. The base dissolves and p-decylacetanilide crystallizes out. 3.5 parts of nitric acid are added, the acetyl compound passes into solution and on pouring the mixture into parts of water, 2-nitro-4-decylacetani1ide separates as a pale yellow solid, which on crystallizing from ethyl alcohol melts at Gil-89 C.

Example 6.The 2-nitro-4-decylacetanilide made in Example 5 is heated for 3 hours, under reflux, with 5 parts of 20% aqueous sodium hydroxide solution. On cooling and dilution with water 2-nitro-4-decylaniline separates. The pure compound is obtained in brown crystals of M. P. 66-67 C. by crystallizing from ethyl alcohol.

Example 7.--5 parts of p-decylaniline are dissolved in parts of 98% sulfuric acid at 0 C. and 4 parts of 90% nitric acid are added at 0 C. After stirring for 2 hours, the nitrated amine is precipitated by pouring the mixture into iced water and then adding an excess of ammonia to baslfy the resulting sulfate. The nitroamine is filtered, washed, dried, and recrystallized from light petroleum. 3-nitro-4decylaniline is obtained as an orange-yellow solid.

Example 8.-p-Tetradecylaniline is used in place of p-decylaniline in Example 3. 2-nitro-4- tetradecylacetanilide is obtained as a pale yellow solid, meltingat 75-76 C.

Example 9.--2-nitro-4-tetradecyla.niline is obtained from the 2-nitro-4-tetradecylacctanilide, which is described in Example 8, by hydrolyzing it by the process described in Example 6. It is a yellow solid, melting at 75-76 C.

Example 10.p-Hexadecylaniline is used in place of p-decylaniline in the process of Example 5. 2-nitro-4-hexadecylacetanilide is obtained as a pale yellow solid.

Example 11.The 2-nitro-4-hexadecylacetanilide which is obtained in Example 10, is bydrolyzed by the process described in Example 6. 2-nitro-4-hexadecylaniline is obtained as a yellow solid, melting at 7980' C.

Example 12.-5 parts of p-hexadecylaniline are dissolved in 20 parts of acetic acid and 180 parts of 98% sulfuric acid are added when phexadecylaniline sulfate separates as a finely-di- Vlded solid. 4 parts of 90% nitric acid and 6 parts of sulfuric acid are then added at 0 C. and the mixture stirred for one hour. The mixture is poured on toice, the sulfate of 3-nitro-4-hexadecylaniline is precipitated, and this is filtered oil and baslfied with ammonia. The crude nitroamine is purified by dissolving in alcoholic hydrochloric acid and crystallizing out the hydrochloride. The crystallized hydrochloride is basifled with ammonia, when 3-nitro-4-hexadecylaniline is obtained as an orange coloured solid, M. P. 71 C.

Example 13.5 parts of 4-dodecy1-2-methylanillne are acetylated and nitrated as described in Example 5 and the resulting product is recrystallized from alcohol. 2-nitro-4-dodecyl-6-methylacetanilide is thus obtained as a very pale yellow solid, M. P. 104 C.

Example 14.-The 2-nitro-4-dodecyl-6-methlyacetanilide, which is obtained in Example 13 is hydrolyzed by the process described in Example 6. 2-nitro-4-dodecyl-G-methylaniline is obtained as a yellow solid.

Example 15.--5 parts of 4-dodecyl-2 -methylaniline are nitrated in 98% sulfuric acid and the resulting product isolated as described in Example 12. is obtained as a brownish-yellow solid.

As many apparently widely different embodl ments of this invention may be made without departing from the spirit and scope thereof, it is to be understood that we do not limit ourselves to 3-Nitro-4-dodecyl-2- or G-methylaniline 70 the specific embodiments thereof except as defined in the appended claims.

in which X is one of the group consisting of hydrogen and an acyl group, one Y is nitro, one Z is an aliphatic radical having 6 to 18 carbon atoms, and the other Y and Zs are at least one of the group consisting of hydrogen, bromo,

chloro, methyl and alkoxy.

2. The compound represented by the formula aikyl NBC-X in which X is one of the group consisting 0t hydrogen and an acyl group, one Y is nitro, alkyl is an aliphatic radical having '6 to 18 carbon atoms, the other Y and 2's are at least one of the group consisting of hydrogen, bromo, chloro, methyl and alkoxy.

3. The compound represented by the formula AIKYIQNHI rectly attached to the benzene nucleus, andin which the benzene nucleus is substituted by at least one of the group consisting of hydrogen, bromo, chloro,methyl, and alkoxy substituents, directly attached to the benzene nucleus.

5. New mononitroalkylacylanilines, in which the alkyl group has 6 to 18 carbon atoms, and is directly attached to the benzene nucleus, and in which the benzene nucleus is substituted .by at least one of the group consisting of hydrogen, bromo, chloro, methyl, and alkoxy substituents, directly attached to the benzene nucleus.

6. The process which comprises nitrating one of the group consisting of alkylaniline compounds and alkylacylaniline compounds in which alkyl is an aliphatic radical directly attached to the henzene nucleus and has 6 to 18 carbon atoms, until the compound is mononitrated.

'7. Process for the manufacture of new mononi- ,troalkylanilines, which comprises mononitrating alkylanilines, in which the alkylgroup has 6 to 18 carbon atoms, and is directly attached to the benzene nucleus, and in which the'benzene nucleus is substituted by at leastone oi the group consisting of hydrogen, bromo, chloro, methyl, and alkoxy substituents, directly attached to the benzene nucleus.

'8. Process for the manufacture of new mononitroalkylacylanilines, which comprises mononitrating alkylacylanilines, in which the alkyl group has 6 to 18 carbon atoms, and is directly attached to the benzene-nucleus, and in which the benzene nucleus is substituted by at least one or the group consisting of hydrogen, bromo,, chloro, methyl, and alkoxy substituents, directly attached to the benzene nucleus.

SAMUEL COFFEY. NORMAN'HULTON HADDOCK. 

